<template>
  <div id="app">
    <div>
      <span>全选:</span>
      <input type="checkbox" v-model="all" />
      <button @click="fn">反选</button>
      <ul>
        <li v-for="(item,index) in arr" :key="index">
          <input type="checkbox" v-model="item.checked" />
          <span>{{item.name}}</span>
        </li>
        
      </ul>
    </div>
  </div>
</template>

<script>
export default {
  data() {
    return {
      arr: [
        {
          name: '猪八戒',
          checked: false,
        },
        {
          name: '孙悟空',
          checked: false,
        },
        {
          name: '唐僧',
          checked: true,
        },
        {
          name: '白龙马',
          checked: false,
        },
      ],
    }
  },
  computed:{
    all:{
      get(){
        return this.arr.every(item=> item.checked)
      },
      set(value){
        this.arr.forEach(item=>item.checked=value)

      }
    }
  },
  methods:{
    fn(){
    this.all=!this.all
  }
  }
  
}
</script>

<style></style>
